How to loop back to previous step until condition is met and to stop on a wait event every time?

[mciprijanovic]

I have workflow with following steps order:

1. Some task
2. Wait for external event
3. Decision which continues if true, goes back to step 1 if false.

How can I achieve the effect that I stop on step 2 every time I reach it? I believe that when I enter step 2 for the first time and go through it, next time it will be considered as unblocked and flow will go. Am I right and how to overcome that and stop every time?
Thanks.